Sunday, April 19, 2015

Addendum - new vs. old Canon 100-400mm

In my previous post on this lens, I used a 1.4x teleconverter on both lenses.  I got a request to repeat the test without the teleconverters, so here are the results.

These are all shot at ISO 400, f/5.6 at 400mm, 1/1600s, autofocus with the center point, RAW.  It is later in the day, and it looks like light clouds and shadows moving in the breeze are slightly changing the lighting between the shots, so caveat emptor.  First the whole image with the old lens:


Next, the new lens:


Here are the locations of the crops I took:


First, the center crop.  The old lens:


The new lens - again, sharper even in the center (although the moving shadows from the windy day make it a little harder to tell):


The left edge crop, the old lens:


The new lens - significantly sharper:


And now, the corner crop, the old lens:


And the new lens.  It is no contest:


The chromatic aberration is not as bad with the old lens without the teleconverter - but the sharpness is still much worse than the new lens.  And autofocus is slower, and the IS is not as capable, and...

Edit - one last thing.  Reading the MTF charts, it seems as if the new lens with a teleconverter should be better than the old lens without a teleconverter.  So, here is a direct comparison - I adjusted the white balance and brightness a bit to try to make the images match a bit better, but otherwise did not modify the images.  I resized the image from the new lens with a 1.4x teleconverter by 1/1.4 and took a crop from the lower left corner of that:


Here is the old lens, at 400mm f/5.6:


And here is the new lens, at 560mm f/8.0 with the 1.4x teleconverter, scaled as mentioned by 1/1.4 or 71.43% to match the pixel scale (without using a sharpening downsample filter):



I'm sold.

Old versus new Canon 100-400mm zoom

Late last year, Canon introduced a new lens, the EF 100-400mm f/4.5-5.6L IS II USM (say that three times fast!).  Reviews held that it was a significant improvement over its predecessor (which is named the same, but does not have the "II" between "IS" and "USM"), and, in fact, was equivalent to their 400mm prime in image quality, but with tons of feature advantages.  I acquired the new lens this week, and have put it through a test to compare, stealing some techniques from my brother-in-law Edward Plumer.

Note - I have an addendum without the teleconverter in the mix.  It does not change the conclusion.

I set the lenses up on a tripod, pointed at a fork in the tree.  The contrast and colors in the tree are similar to those I find when taking wildlife shots.  Image stabilization was disabled in both lenses.  The new lens was attached to a Canon Expander 1.4x III and the old was attached to a Canon Expander 1.4x II (the previous model).

The lenses were attached to a Canon 7D Mark II camera, which was allowed to autofocus with the center point (a significant advantage of this camera - it autofocuses up to a minimum aperture of f/8).  Exposure parameters were manual - ISO 400, 1/640s exposure, f/8 at a 560mm net focal length - and images were shot RAW to avoid in-camera lens correction (although it may still have happened, I did not dig through the menus to find out).  I put the camera on a 10s timer to reduce lens shake from pressing the shutter button.  I took three images with each camera, and selected the best of the three for this analysis.

Here are the results.  First, the old lens:


 Not a bad image - the bokeh is reasonable, the contrast seems OK.  Now the new lens:



Again, at this size, not a bad image.  The bokeh seems a little softer, which is good.  If I only ever looked at pictures this size, it would be a hard choice (although the new lens auto-focuses significantly faster than the old).  However, with wildlife, the images are almost always cropped since the birds are so tiny and so far away.  So, I took some crops.  Here are the locations of the crops:


First, the center crop.  This is the point at which autofocus was locked.  Here is the old lens:


Hmm.  A little soft.  Let's take a look at the new lens:


Obviously better.  Maybe 50% better?  Take a look now at the left edge crop from the old lens:


Definitely soft.  Is that a little chromatic aberration creeping in?  Here comes the new lens:


It's no contest.  And for wildlife, edge performance is important, even though I autofocus for the center.  Sometimes the animal is moving so fast that my picture is snapped with it close to the edge of the frame.  I've lost many shots to the softness of the old lens.  And now, for the coup de grace, the corner crop.  The old lens:


This crop is, simply put, a mess.  Chromatic aberration is all over the place, and the image is just ugly.  Here is the new lens:


The detail in the corner on the new lens looks about as sharp as the detail in the center.  In fact, the detail in the corner is shaper than the center on the old lens.

I'd say we have a winner.  Other improvements in the new lens include: a 9-blade iris (versus 8 in the old lens), image stabilization supposedly good to 4 stops (vs. 1.5 in the old lens), improved anti-reflection coatings, rotating zoom ring versus push-pull, improved weather sealing, and an improved lens cap which makes it possible to put it on and take it off with the lens hood attached.

In summary - well worth the 50% price premium.  This is probably a 10x better lens.